Neuron populations in the hypothalamus and hindbrain form nodes within a larger distributed network to control multiple aspects of feeding behavior in mammals. The goal of this project is to identify and map arcade hypothalamic circuits that respond to circulating hormones that control feeding behavior. At the heart of this project lies a novel combination of functional neuroanatomical techniques: tract-tracing, wide-field and multi- fluorescence imaging, reference atlas-based mapping, and data deposition within an online neuron informatics database. These methods are being brought to bear on the arcuate hypothalamus, because it has remained a relatively uncharted and poorly defined brain structure that is otherwise critical for feeding behavior. Knowledge of the basic circuit organization of this structure, through its complete three dimensional expanse, is critical for scientists to be able to further experimentally manipulate selected sub-populations of neurons in this structure to study various aspects of feeding control. This, in turn, is expected to yield novl targets within the brain suitable for designing rationale therapeutics and treatments to help prevent or mitigate the effects of obesity, overeating, and metabolic disorders.